Comments on: The Javascript Dollar Sign ($) Function

By: Chris Herdt

Chris Herdt — Thu, 20 Oct 2011 13:38:42 +0000

Dominik: I agree, although at this point in time the $() is well-established. There's a substantial codebase out there that uses it, so I don't think it's going anywhere soon. Regarding jQuery, $() can also be written as jQuery(), so built-in is the option to use a more explicit function name (see jQuery API). Prototype, on the other hand, does not seem to offer the same: Prototype API. You could create your own alias (e.g. getElements = $), but that creates its own hassles.

By: Dominik Kaspar

Dominik Kaspar — Thu, 20 Oct 2011 09:13:04 +0000

Spelling out meaningful function names is always better than trying to prevent bytes added to your code.

By: Bill

Bill — Fri, 19 Aug 2011 14:54:32 +0000

Thanks Chris, I just started looking at JQuery and then had to find your post. Scrontch is right – they just slapped it in there and expected me to know what they meant by it.

By: Chris Herdt

Chris Herdt — Mon, 21 Mar 2011 13:37:37 +0000

I can’t say what exactly it means in that context without diving into the project code, but in general it is just a variable reference. In this case it is the variable reference for the argument passed to an anonymous function.

By: Andrew Pennebaker

Andrew Pennebaker — Sat, 19 Mar 2011 22:47:56 +0000

Thanks for the clarification. But what does the dollar sign mean in this code?

// From TryHaskell
// https://github.com/chrisdone/tryhaskell

function ($) {
…
}

By: Scrontch

Scrontch — Wed, 17 Nov 2010 17:11:41 +0000

Excellent. Saved me from lots of confusion and searching.
JS libraries such as JQuery take this shorthand definition for granted. So without knowing this, their tutorials and example codes become difficult to understand for the newcomer.
And thanks for putting “Dollar Sign” in the post title, because searching for “Javascript $” doesn’t give any useful results

By: Brad

Brad — Mon, 25 Oct 2010 23:38:47 +0000

Nice. Handy shortcut but hard to decipher without prior knowledge of it. Thanks for posting!

By: walkman69

walkman69 — Tue, 22 Jun 2010 14:17:35 +0000

isn’t the “_” meant to indicate that you shouldn’t tamper with this thing since it’s used internally?. Kind of private? ^^

By: seo web design company

seo web design company — Tue, 23 Jun 2009 23:24:07 +0000

I would like to point out that the JS 1.1 spec (’96) states that the ‘$’ and ‘_’ can be used in identifiers and are valid.
url: planetpdf.com/codecuts/pdfs/tutorial/jsspec.pdf
essentially making the use of $() {} a valid function identifier. Last I recalled the ECMA Script language was developed after (and based on) Javascript by Netscape and JScript from Microsoft.

By: Chris Herdt

Chris Herdt — Fri, 11 Jul 2008 17:36:03 +0000

@Phil:

It looks like that’s some jQuery code. $(‘.print_toggle’) should return all elements with the class print_toggle, and .toggle(‘fast’) indicates that the specified element(s) should show/hide (depending on their current state) fast (describes the animation).

The ‘fast’ argument should be superfluous, as according to the jQuery docs, toggle() doesn’t take any arguments–but I notice that the transition is animated on http://www.rjobrien.com/. Maybe someone with more experience in jQuery can answer that.

http://docs.jquery.com/Selectors/class
http://docs.jquery.com/Effects/toggle

It’s a pretty slick effect for very little code.